Soil carbon feedbacks to reintroduction of large herbivores in Arctic landscapes: Decelerating climate warming?
Name of applicant
Jeppe Ågård Kristensen
Institution
University of Oxford
Amount
DKK 1,332,731
Year
2020
Type of grant
Visiting Fellowships at University of Oxford
What?
Introduction of large herbivores in ecosystems where they are currently extirpated is a way of restoring natural ecosystem dynamics. Large animals effectively increase the landscape variation and in turn biodiversity. However, how large animals influence other ecosystem functions, such as carbon storage, is not well understood. Dragging carbon out of the atmosphere and into biomass in vegetation and soils is often highlighted as a promising strategy for reducing climate warming. However, in Arctic tundra carbon is currently being released to the atmosphere, particularly due to warmer soils. HERBIVARC studies the potential of large herbivores to decelerate this release of C from soils to the atmosphere by stabilising the carbon in the soil.
Why?
Over the last few decades, our knowledge about Arctic ecosystem responses to climate warming has increased exponentially. Yet, the role of large herbivores in regulating interactions between vegetation and soils and the combined impact on climate feedbacks remains poorly explored. Soils are important global carbon (C) stores, and as the Arctic region warms about 4 times faster than the global average, the Arctic soil C-pool is currently being released to the atmosphere as greenhouse gasses. Introduction of large herbivores may have the ability to decelerate this trend, partly through increasing the soil C-input and -stabilisation. HERBIVARC will elucidate changes in soil C-dynamics caused by herbivore introduction in the tundra and estimate its potential for climate change mitigation.
How?
In 1996, an assembly of large herbivores including bison, yakutian horses and reindeer were introduced into an area called the Pleistocene Park (PP) in Northeastern Siberia. This experiment has created a unique opportunity to study the effects of herbivores on ecosystem dynamics on timescales relevant for climate change. In HERBIVARC, we will combine field-based estimates of greenhouse gas effluxes from soils inside and outside the PP. Moreover, we will take soil samples for studying soil C-mobilisation and -stabilisation under laboratory conditions. We will explore the potential biological drivers of the changes soil C dynamics by quantifying the changes in soil faunal and microbial communities associated with large herbivore introduction.